Bioindicators of Mercury in Riverine Systems

This study focuses on the bioaccumulation and biomagnification of mercury in freshwater food webs, with emphasis on bioindicators, such as macroinvertebrates, crayfish, and river otters. Despite regulatory efforts and advancements in monitoring, significant gaps remain in understanding mercury dynamics in freshwater systems—especially regarding its transport, methylation, and bioavailability across different ecosystems. To address these knowledge gaps, this study adopts a biocentric approach, emphasizing the role of living organisms in their environment. By utilizing macroinvertebrates, crayfish, and river otters as bioindicators, we aim to assess mercury bioavailability and distribution. These organisms provide varying temporal and spatial scales of mercury accumulation, offering a detailed snapshot of ecosystem health. The research objectives were to identify specific macroinvertebrate taxa as indicator species of pH, assess mercury concentrations and tolerance to mercury in crayfish, and quantify mercury levels in riverine food webs involving crayfish, fish, and river otters to enhance our understanding of mercury transport in freshwater systems.